1. Field of the Invention
This invention relates to an air spray device, more particularly to an air spray device with a telescopic spray tube that is convenient to use and store.
2. Description of the Related Art
Referring to FIG. 1, a conventional air spray device is shown to include a barrel 1 with a passage 102 which has an inlet 103 and an outlet 104, a valve body 3 which is disposed in the passage 102 between the inlet 103 and the outlet 104 and which has upper and lower O-rings 302 and an annular groove 301, an actuator 5 which is pivotally disposed on the barrel 1 via a pivot pin 4 to actuate the valve body 3 so as to align the annular groove 301 with the inlet 103 and the outlet 104 in order to permit compressed air from the inlet 103 to flow through the outlet 104 and to spray out from a spray tube 6 that is connected to the outlet 104 so as to remove dust on an object for cleaning purposes, and a biasing member 2 which can bias the valve body 3 to align one of the upper and lower O-rings 302 with the inlet 103 and the outlet 104 to interrupt the fluid communication therebetween.
Since the length of the spray tube 6 is fixed, dust to be removed from the object may fly over the user during operation. This is particularly undesirable when the air spray device is applied in conjunction with a painting and coating device. In addition, after use, some painting and coating material may be left in the nozzle portion 61, thereby resulting in inconvenient cleaning thereof. Moreover, numerous air spray devices are required for operating with different materials of painting, thereby resulting in inconvenience during usage.
The object of the present invention is to provide an air spray device in which a spray tube has a plurality of tube portions telescopically fitted over each other so as to be stretchable and retractable for added convenience during storage and use.
According to this invention, the air spray device comprises a barrel with an inner surrounding wall to define a passage which has an inlet and an outlet downstream of the inlet. A controlling member includes a valve body which is disposed in the passage between the inlet and the outlet, and a stem portion which has an inner end engaging the valve body and an outer end extending from the inner end and transversely and outwardly of the inner surrounding wall so as to be actuated to move the valve body to permit fluid communication between the inlet and the outlet. A biasing member is disposed to bias the valve body to interrupt the fluid communication between the inlet and the outlet. An actuator is disposed on the barrel to actuate the outer end of the stem portion to move the valve body against a biasing action of the biasing member. A spray tube includes first and second tube portions. The first tube portion has a first proximate end which is connected to and which is in fluid communication with the outlet, a first distal end opposite to the first proximate end in a longitudinal direction and downstream of the first proximate end, and a first intermediate tubular portion interposed between the first proximate and distal ends. The first intermediate tubular portion includes a first outer tubular wall surface, and a first inner tubular wall surface which defines a first conduit opposite to the first outer tubular wall surface radially and disposed between and communicating with the first proximate and distal ends. The second tube portion has a second proximate end which is inserted into the first conduit, a second distal end which is disposed opposite to the second proximate end in the longitudinal direction and downstream of the second proximate end and which extends outwardly of the first distal end, and a second intermediate tubular portion which is interposed between the second proximate and distal ends. The second intermediate tubular portion includes a second outer tubular wall surface to be telescopically fitted in the first conduit in the longitudinal direction and to be slidable between a stretched position, where the second proximate end is close to the first distal end, and a retracted position, where the second proximate end is close to the first proximate end, and a second inner tubular wall surface opposite to the second outer tubular wall surface radially and defining a second conduit that is in fluid communication with the first conduit. A nozzle portion is disposed outwardly of the second distal end and distal to the second proximate end, and is fluidly communicated with the second conduit. A first retaining member is disposed on and extends radially and inwardly from the first inner tubular wall surface proximate to the first proximate end so as to arrest further movement of the second proximate end toward the first proximate end in the retracted position. A second retaining member is disposed between the first distal end and the second outer tubular wall surface proximate to the second proximate end to arrest further movement of the second proximate end toward the first distal end in the stretched position.